Synthesis of amino polycarboxylic acids of the adamantane series

The Ritter reaction of dibasic carboxylic acids of the adamantane series with carboxy and carboxymethyl groups attached to bridgehead carbon atoms afforded a number of amino polycarboxylic acids.     

The thermodynamics of ionization of polycarboxylic acids

Thermodynamic parameters for the successive ionizations of a number of monomeric polycarboxylic acids have been determined from a temperature-dependence study of the ionization constants calculated from potentiometric data obtained using cells without liquid junction. Specifically the acids are: 1,2,3-propanetri-; 1,2,3,4-butanetetra-; 1,3-benzenedi-; 1,2,3-, 1,2,4-, and 1,3,5-benzenetri-; 1,2,4,5-benzenetetra-; and 1,2,3,4,5,6-benzenehexacarboxylic acids. The data are critically discussed in terms of the common models of ionization and of reactivity effects of substituents on ionization for monomeric and polymeric polybasic acids.Abstracted from M.B.T.'s doctoral disseration, Oklahoma State University, May 1972. Copies of the computer programs and directions for their use will be available from University microfilms.     

Synthesis and investigation of polymers based on the nitriles of polycarboxylic acids and diamines

The influence of the reaction medium on the polycondensation of the tetranitriles of tetracarboxylic acids and diamines has been investigated. The reaction in phenol and cresols yields polymers with macroheterocycles in the chain—polyhexasocyclanes. If phenols with electron-accepting substituents are used as reaction medium, nonmacrocyclic polymers with side aroxyl groups in the chain, polyisoindoxazenes—are formed. The properties of these polymers were studied. Macroheterocyclic compounds formed by condensation of phthalodinitrile with diamines can be used as one of the initial substances in polyhexasocyclane synthesis. Polyamidohexasocyclanes were prepared by polycondensation of macroheterocycles with dicarboxylic acid dichlorides. Some regularities of their formation and their properties were investigated.     

液相色谱-质谱法分析黑碳的分子标志物——苯多羧酸和硝基苯多羧酸

苯多羧酸法是定量检测黑碳和溶解态黑碳的重要分子标志物法,其中苯多羧酸和硝基苯多羧酸的分离和定量是关键环节。本文建立了苯多羧酸和硝基苯多羧酸的液相色谱-质谱分析方法,利用质谱的定性能力解决了部分苯多羧酸和硝基苯多羧酸化合物在缺乏标准品情况下的定性问题。用Phenomenex Synergi Polar RP分离柱,柱温为35 ℃,流动相为0.5%(体积分数)甲酸水溶液和甲醇,流速为0.5 mL/min,梯度洗脱,以电喷雾离子源负离子全扫描和选择扫描模式进行离子阱质谱检测,同时利用串联的二极管阵列检测器采集三维紫外光谱数据。在实际样品检测中,14个含3个及以上羧基的苯多羧酸和硝基苯多羧酸化合物获得良好分离。此方法简化并加快了苯多羧酸法定量黑碳和溶解态黑碳的分析过程,可满足环境样品中黑碳和溶解态黑碳的分析,促进了苯多羧酸法应用的普及。     

The solubilities of benzene polycarboxylic acids in water

The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities.     

Capillary electrochromatographic analysis of aliphatic mono- and polycarboxylic acids

The parameters influencing the electrochromatographic separation of aliphatic organic acids in a capillary column with a wall-coated macrocyclic polyamine have been studied. Indirect detection using chromate, pyromellitate, trimellitate, o-phthalate, benzoate and acetate as background electrolytes has been tested. A complete separation of polyprotic acids could be achieved with pyromellitate buffer (7.5 mM, pH 6.5), and satisfactory results for the simultaneous separation of monoprotic acids and polyprotic acids were found using a capillary column of 70 cm (50 cm effective length)x75 microm inner diameter, electrokinetic injection (-10 kV, 10 s), benzoate buffer (6 mM, pH 4.6), separation voltage of -10 kV, and detection at 220 nm. For the separation of the geometric isomers fumarate and maleate, acetate buffer was found the best choice among the background electrolytes tested. The method so established has been applied to the determination of organic acids in soy sauce, brandy, lemon juice, spinach juice and cigarette. From the retention behavior, it was found that the separation mechanism on the bonded phase was influenced by the macrocyclic effect, electrostatic attraction, hydrogen bonding, van der Waals forces, and anion exchange, in addition to the differences in electrophoretic mobility.     

The role of polycarboxylic acids in calcium phosphate mineralization

The role of two polyelectrolytes, poly-L-glutamate and poly-L-aspartate, in the growth of calcium phosphate crystal phases, has been investigated at constant supersaturation. Both molecules are strong inhibitors of HAP growth when present in the solution phase but also act as hydroxyapatite and (octacalcium phosphate)-like crystal nucleators when adsorbed on germanium surfaces. The structure of the polymers in solution is presented and various adsorption models are analyzed. A "train-loop" structure of these long, flexible chain polymers on the crystal surface is consistent with all the adsorption (experimental and theoretical), inhibition, and electrophoretic mobility results.     

Determination of thorium in zirconium-hafnium mixtures by aromatic polycarboxylic acids

Summary Results are presented for 1,3,5-benzenetricarboxylic (trimesic), 1,2,4-benzenetricarboxylic (trimellitic) and 1,2,4,5-benzenetetracarboxylic (pyromellitic) acids as precipitants for thorium. Trimesic and pyromellitic acids have been found to be better reagents than trimellitic acid. Thorium and zirconium-hafnium mixtures can be separated by precipitating zirconium-hafnium first in 0.5–0.8 N acid solution and then precipitating thorium in the filtrate at 3–4 pH. The separations are quite reproducible. The precipitates in all cases are ignited to the respective oxides. 5–10 mg samples of thorium can be estimated and separated from 10–50 mg samples of zirconium and/or hafnium. Results of investigations on interferences of cations and anions and pyrolysis curves for the decomposition of precipitates are presented.

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Zusammenfassung Als Fällungsmittel fÜr Thorium wurden 1,3,5-Benzoltricarbonsäure (Trimesinsäure), 1,2,4,5-Benzoltetracarbonsäure (Pyromellitsäure) und 1,2,4-Benzoltricarbonsäure (Trimellitsäure) untersucht, wobei die beiden ersten sich als gÜnstiger erwiesen haben. Gemische von Thorium und Zirkonium/Hafnium kÖnnen getrennt werden, indem man zuerst Zr/Hf in 0,5–0,8 n saurer LÖsung fällt und anschlie\end Thorium aus dem Filtrat bei pH 3–4 niederschlägt. Die Trennung ist gut reproduzierbar. Die Niederschläge werden jeweils zu den entsprechenden Oxiden verglÜht. 5–10 mg Th kÖnnen von 10–50 mg Zr und/oder Hf getrennt werden. StÖrungen durch andere Kationen und Anionen wurden untersucht und Pyrolysekurven fÜr die Zersetzung der Niederschläge aufgestellt.

     

Apparent dissociation constants of polycarboxylic acids in presence of polycations

The dissociation behaviour of poly(acrylic acid) and poly(ethylene-alt-maleic acid) has been investigated by both classical potentiometric titration and colloid titration as an alternative way. In the case of colloid titration, the monovalent counterions are assumed to be replaced by the oppositely charged polycation in the course of titration, so that the total concentration of anionic groups of the polycarboxylic acid is determined. As a consequence the apparent dissociation constants determined by polyelectrolyte complex formation do not depend on the degree of dissociation. In contrast to this finding, potentiometric titration is known to result in apparent dissociation constants which decrease with increasing degree of dissociation. The release of protons from the acid groups of the polycarboxylic acids is promoted by the complex formation with the strong cationic polyelectrolyte.     

Infrared spectroscopy studies of the cyclic anhydride as the intermediate for the ester crosslinking of cotton cellulose by polycarboxylic acids. II. Comparison of different polycarboxylic acids

Polycarboxylic acids have been used as crosslinking agents for cotton cellulose. In our previous research, we used Fourier transform infrared (FT-IR) spectroscopy to investigate the formation of five-membered cyclic anhydride intermediates on cotton fabric by different polycarboxylic acids. In this research, we found that those polycarboxylic acids capable of forming both five- and six-membered cyclic anhydrides form only five-membered cyclic anhydrides. We compared the effectiveness of the polycarboxylic acids with different molecular structures for esterifying cellulose. Those polycarboxylic acids, which have their carboxyl groups bonded to the adjacent carbons of their molecular backbones and are capable of forming five-membered cyclic anhydrides, are more effective for esterifying cellulose than those polycarboxylic acids having their carboxyl groups bonded to the alternative carbons. The only six-membered cyclic anhydride identified is the anhydride formed on the cotton fabric treated with poly(acrylic acid). © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of a redox- and light-sensitive MRI contrast agent

A redox- and light-sensitive, T₁-weighted magnetic resonance imaging (MRI) contrast agent, which tethers a spiropyran (SP)/merocyanine (MC) motif to a Gd-DO3A moiety was synthesized and characterized. When in the dark, the probe is in its MC form, which has an r₁ relaxivity of 2.51 m M⁻¹ s⁻¹ (60 MHz, 37 °C). After irradiation with visible light or mixing with NADH, the probe experiences an isomerization and the r₁ relaxivity decreased 18% and 26%, respectively. Additionally, the signal intensity in MRI showed an observable decrease after the compound was mixed with NADH.     

Simultaneous determination of polycarboxylic acids by capillary electrophoresis with a copper electrode

The simultaneous determination of polycarboxylic acids including oxalic acid, citric acid, malonic acid, malic acid, tartaric acid, aspartic acid and glutamic acid was achieved by capillary electrophoresis with a copper disk electrode (d = 200 microm). In the system. 0.2 mmol/l cetylpridinium bromide (CPB) was used as an electroosmotic flow (EOF) modifier to reverse the direction of EOF. The effects of the solution pH and CPB concentration on separation were evaluated to achieve the optimum separation conditions. At the working potential of +0.14 V (vs. saturated calomel electrode), the calibration curves for all polycarboxylic acids studied were linear with 2 approximately 3-orders of magnitude and all the detection limits (S/N = 3) were below 15 fmol except malonic acid. Furthermore, the oxalic and citric acids in urine were successfully separated and determined with high sensitivity.     

Rate constants for the reaction of OH radicals with some amino polycarboxylic acids

Rate constants of OH radical reaction with some amino polycarboxylic acids (APCAs) such as EDTA, DTPA, HEDTA, NTA, and HIDA have been determined at different pHs using pulse radiolysis competition kinetics method with thiocyanate as the reference solute. The rate constants varied with pH (possibly due to their various pKs) and the plots of rate constants vs. pH are given. Rate constants for OH radical reaction with the various acid–base forms of these amino polycarboxylic acids are estimated from the plateau values in the plots. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 99–104, 2000     

Synthesis and dyeing performance of a novel polycarboxylic acid azo dye

A novel reactive polycarboxylic acid dye was synthesized by the reaction of polymaleic anhydride（PMA） with 3-methyl-1-（4- sulfonylphenyl）-4-（4-aminophenylazo）-2-pyrazoline-5-one.The structure of the novel dye was characterized by FTIR,UV-vis and ¹³C NMR spectra.The dyeing properties of dye on cotton were tested,and the novel dye possessed high fixation and good fastness.     

Identification and quantification of cotton-bound,cyclic polycarboxylic acids by means of isocratic HPLC

Cotton fabrics are modified by means of polycarboxylic acids (PCA) in combination with an inorganic catalyst in order to impart durable press properties. To evaluate the effectiveness of cyclic PCA, 100% cotton fabrics were treated with 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (CH-HCA), 1,3,5-cyclohexanetricarboxylic acid (CH-TCA), 1,2,3,4-cyclopentanetetracarboxylic acid (CP-TCA), and 1,2,3,4-tetrahydrofurantetracarboxylic acid (THF-TCA) in combination with sodium hypophosphite (SHP) as catalyst. The amount of PCA that reacted with the cellulosic material was determined by means of isocratic HPLC (Aminex HPX-87-H). The results clearly indicate that the cyclic PCA are less effective in respect of durable press performance. CH-TCA does not react with the cellulosic material thus confirming the assumption that the crosslinking reaction between PCA and the cellulose proceeds via a five-membered cyclic anhydride.     

Enhancement of the reductive transformation of pentachlorophenol by polycarboxylic acids at the iron oxide-water interface

The enhancement effect of polycarboxylic acids on reductive dechlorination transformation of pentachlorophenol (PCP) reacting with iron oxides was studied in anoxic suspension. Batch experiments were performed with three species of iron oxides (goethite, lepidocrocite and hematite) and four species of polycarboxylic acids (oxalate, citrate, succinate, and tartrate) through anoxic abiotic reactors. The chemical analyses and morphological observation from scanning and transmission electron microscopy showed that different combinations between polycarboxylic acids and iron oxides produced distinct contents of Fe(II)-polycarboxylic ligand complexes, which significantly enhanced PCP transformation. Generation of the surface-bound Fe(II) depended on concentration of polycarboxylic acids. The optimal concentration for the enhancement was 2.0 mM oxalic acid. The dechlorination mechanism was further demonstrated by generation of chloride ions. The results suggest that surface-bound Fe(II) formed on the iron oxides surface appears to be a key factor in enhancing PCP transformation, and the mole ratio of oxalate to surface-bound Fe(II) (oxalate/Fe(II)) acted as an indicator of the enhancement effect. The enhancement mechanism attributes to strong nucleophilic ability and low reductive potential of the equivalent Fe(II)-polycarboxylate complexes. Therefore, the enhancement effects might be helpful for understanding the natural attenuation of reducible organic pollutants at the interface of contaminated soil in anoxic condition.     

Syntheses and photocatalytic performances of four coordination complexes constructed from 1,10-phenanthroline and polycarboxylic acids

Four coordination complexes of copper(II) and iron(II), namely [CuCl(phen)₂](5-NO₂-Hipa)·2H₂O (BUC-10), [Cu(phen)(3,4-H₂dczpb)(H₂O)]·H₂O (BUC-11), [Fe(phen)(L)(H₂O)]₂ (BUC-12), and [Fe(phen)₃](3,4-H₃dczpb)₂·0.6H₂O (BUC-13) (phen = 1,10-phenanthroline; 5-NO₂-H₂ipa = 5-nitroisophthalic acid; 3,4-H₄dczpb = 3,4-dicarboxyl-(3′,4′-dicarboxylazophenyl) benzene; L = 6,12-dihydroxy-1,2,6,12-tetrahydroindazolo[2,1-a]indazole-1,7-dicarboxylic acid), have been synthesized under hydrothermal conditions. All four complexes were characterized by single-crystal X-ray diffraction, FTIR, elemental analysis and UV–Vis diffuse reflection spectroscopy. The photocatalytic performances of the complexes for decomposition of methylene blue under UV irradiation were also investigated.     

Synthesis of novel 1,2,3-triazole based polycarboxylic acid functionalised ligands for MOF systems

Copper catalysed click reactions are excellent tools to generate various 1,2,3-triazole linked polytopic aromatic carboxylates. The general reaction route involves protection of the carboxylates before proceeding with the click reaction. These polycarboxylate azoles are conveniently prepared for potential utility as novel key building blocks for metal organic frameworks. In one case, the ligand crystallises into a solid structure containing 1D, 2D and 3D features, based on a zigzag 1D structure, a ‘chicken mesh’-like 2D structure and a 3D structure with very well-defined channels.     

Interconversion of host–guest components in supramolecular assemblies of polycarboxylic acids and reduced Schiff bases

Eight supramolecular assemblies of benzene-1,3,5-tricarboxylic acid (H₃BTC) and benzene-1,2,4,5-tetracarboxylic acid (H₄BTtC) with reduced Schiff base of flexible backbone having phenolic and pyridyl groups, i.e., 1,2-bis(2-hydroxybenzylamino)ethane, 1,3-bis(2-hydroxybenzylamino)propane, 1,4-bis(2-hydroxybenzylamino)butane and 1,4-bis(4-pyridinylmethylamino)butane have been constructed by proton transfer reaction. H₃BTC forms host–guest type assemblies with amines having phenolic functionality, while a layered structure was obtained with pyridyl functionalized amine. H₄BTtC also formed host–guest assemblies with the diamines where reduced Schiff base acts as host and acid moiety acts as the guest. Different conformations of the diamines were observed in these assemblies. Theoretical studies were performed to analyze the effect of varied chain lengths of diamines on hydrogen bond interaction energy of the adducts.